shocking new allegations about the role the church of scientology played in tom cruise and katie holmes' courtship and marriage. >>> and terrifying plunge. an acrobat slips and falls while attempting a daring high wire walk. but don't worry, as bad as it looks, he's doing fine today. captions paid for by nbc-universal television >>> good morning, everyone. welcome to "today" on a sunday morning. i'm lester holt. >> i'm jenna wolfe. the whole practice makes perfect doesn't apply when you're high wiring across large -- >> i was just saying that we don't have a net for what we do. >> which in many ways is exactly the same thing. >> the same thing. >> we're talking about the heat wave this morning. it's been brutal over the last couple of weeks, in some places even deadly, being blamed for 61 deaths. >> finally it is set to break in many places starting today. if you live out west, look out. we'll tell you more about that in a moment with the forecast. >>> then, is your computer a ticking time bomb? thousands of people might not be able to get on the internet starting tomorrow because of a